High speed printers need to maximize throughput. One aspect of ensuring maximum throughput is minimizing printer downtime for replenishment of consumable resources. Many printers today provide some alert when certain printer resources are close to becoming depleted or have been depleted. For instance, printers typically include a small Liquid Crystal Display (LCD) screen to display a message that toner is low, paper is out, etc. Alternatively, the printer driver may send a message for display at a computer connected to the printer indicating which resource is low/depleted. To implement such alert systems, sensors are used to detect when a resource is depleted. For instance, the paper tray would include an electrical or electromechanical sensor to detect when the paper tray is empty. A toner and oil cartridge would include sensors to detect when the toner level is near or at empty. The sensor, upon detecting that the resource is close to or at depletion, would signal the printer processor and the printer processor would, in response, send an alert message to an LCD screen at the printer or to a printer management software program running on an attached computer.
Normally, network-connected self-service printers depend on the printer user to replenish consumable resources that have been depleted. Thus, if a printer runs out of a consumable after a job starts, the printer stops and waits for service. Throughput drops to zero. Such inefficiency creates a need for managing print jobs in a manner that eliminates or minimizes printers stopping in the middle of a job due to a lack of consumable resources.